| Recently CFG-pile composite foundation is applied to deal with soft soil foundation in highway project., as a measure of the treatment of soft soil foundation,CFG-pile composite foundation posseses the following merits:small settlement,high bearing capacity rapid stability,short time limit for a project, therefore, it achieves better economic benefit and social benefit. however,in the present criterion,the design method relating to CFG-pile composite foundation is on the premise that the foundation is rigid. If the method is directly used to design CFG-pile composite foundation under flexible foundation like embankment load,it will result in remarkable difference between computation value and true value. So the research on mechanics character of CFG-pile composite foundation under embankment load will bring importantly practical meaning.In the paper, Firstly a model of CFG-pile composite foundation under embankment load has been established by adopting plane strain FEM through ABAQUS FEM software, in which elastic-plasticity of soil and interaction between pile and soil have been taken into consideration. Then a study on the factors affecting mechanics character( pile-soil stress ratio ri) of composite foundation has been done. The factors mainly include load level(P),pile spacing( D),pile-length(Lp),pile-soilrelative stiffness (Ep/Es1),cusion thickness(t) and module(Ec) relative stiffness between soil at the bottom of piles and soil among piles(Es2/Es1) and embankment soil module(Es3 . The relationship between each influence factor and pile-soil stress ratio( n )is given by the simulative results and the reason is analysed. Besides , an elementary study is done on the plasticity movement trend of soil.Finally, two cases.have been numerically analysed by using FEM and by contrast with the results of in-situ test, the results of numerical analysis are basically reasonable,which proves the regularity of CFG-pile composite foundation through FEM can be mastered.
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